I finally upgraded RAM in my beloved 4550 to 1GB. I replaced 512MB PC2700 (333MHz) with 1GB PC3200 (400MHz) with hope that I can get faster speed (400MHz) as well as bigger memory. However, the BIOS setup still shows the 1GB RAM at 333MHz. What should I do make it work at 400MHz?
looking at you system SPECS Memory is dependant on the processor installed. This will then set the FSB of either 333 or 400 mhz. So you need to change your processore to one that will use the 400 mhz FSB
Try running CPU-z and see what it reports
If the FSB of your processor(on the mobo) is 533MHz then the freq of the memory will be down clocked to 333MHz as it cannot support higher speeds